Search

Peptide nucleic acid (PNA) is a nucleic acid mimic in which the deoxyribose-phosphate was replaced by a peptide-like backbone. The absence of negative charge in the PNA backbone leads to several unique behaviors including a stronger binding and salt independency of the PNA-DNA duplex stability. However, PNA possesses poor aqueous solubility and cannot directly penetrate cell membranes. These are major obstacles that limit in vivo applications of PNA. In previous strategies, the PNA can be conjugated to macromolecular carriers or modified with positively charged side chains such as guanidinium groups to improve the aqueous solubility and cell permeability. In general, a preformed modified PNA monomer was required. In this study, a new approach for post-synthetic modification of PNA backbone with one or more hydrophilic groups was proposed. The PNA used in this study was the conformationally constrained pyrrolidinyl PNA with prolyl-2-aminocyclopentanecarboxylic acid dipeptide backbone (acpcPNA) that shows several advantages over the conventional PNA. The aldehyde modifiers carrying different linkers (alkylene and oligo(ethylene glycol)) and end groups (-OH, -NH

Despite many potent biological activities, retinoids such as retinoic acid (RA) and retinal possess dose-related broad side effects. In this study, we show that this problem, which has been unsolvable for a long time, can be tackled through a controlled release strategy in which retinal is continuously delivered to the skin via sustained release from proretinal nanoparticles. The water dispersible proretinal nanoparticles are stable when kept in water at neutral pH and at room temperature for 8 months under light-proof conditions, and show sustained release of retinal into human synthetic sebum at a pH of 5. In the daily topical application tests performed for 4 weeks on rats’ skin, the nanoparticles showed superior ability to increase epidermal thickness compared to RA and retinal, with no skin irritation observed for the proretinal particles, but severe skin irritation observed for RA and free retinal. When tested under occlusion conditions in human volunteers, insignificant skin irritation was observed for the proretinal nanoparticles. The 12-week, double-blind, split-face study on human volunteers indicates better antiaging efficacy of the particles as compared to the free RA., Video abstract

A great challenge exists in finding safe, simple, and effective delivery strategies to bring matters across cell membrane. Popular methods such as viral vectors, positively charged particles and cell penetrating peptides possess some of the following drawbacks: safety issues, lysosome trapping, limited loading capacity, and toxicity, whereas electroporation produces severe damages on both cargoes and cells. Here, we show that a serendipitously discovered, relatively nontoxic, water dispersible, stable, negatively charged, oxidized carbon nanoparticle, prepared from graphite, could deliver macromolecules into cells, without getting trapped in a lysosome. The ability of the particles to induce transient pores on lipid bilayer membranes of cell-sized liposomes was demonstrated. Delivering 12-base-long pyrrolidinyl peptide nucleic acids with d-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbone (acpcPNA) complementary to the antisense strand of the NF-κB binding site in the promoter region of the Il6 gene into the macrophage cell line, RAW 264.7, by our particles resulted in an obvious accumulation of the acpcPNAs in the nucleus and decreased Il6 mRNA and IL-6 protein levels upon stimulation. We anticipate this work to be a starting point in a new drug delivery strategy, which involves the nanoparticle that can induce a transient pore on the lipid bilayer membrane.

The development of carriers to sustain drugs at stomach surface is an attractive strategy to increase drug bioavailability locally and systematically. So far, the only reported carrier that can form a covalent bond with mucus, the thiolated carrier, relies on a reversible disulfide exchange reaction between thiols on the carrier and disulfide bridges on the mucus. Here we show the design and fabrication of a cellulose carrier with tethering acrylate groups (denoted here as clickable carrier) that, under a nontoxic condition, can efficiently react with thiols on biomaterials in situ through the thermodynamically driven and kinetically probable Michael thiol-ene click reaction. Here we show the attachments of the clickable carriers to a mucin protein, a surface of human laryngeal carcinoma cells, and a surface of a fresh porcine stomach. We also show that the required thiol moieties can be generated in situ by reducing existing cystine disulfide bridges with either the edible vitamin C or the relatively nontoxic tris(2-carboxyethyl) phosphine. Comparing to a control carrier, the clickable carrier can increase some drug concentrations in an ex vivo stomach tissue, and improve the Helicobacter pylori treatment in infected C57BL/6 mice.

Porntip Pan-In,1,2 Supason Wanichwecharungruang,3,4 Justin Hanes,2,5 Anthony J Kim2,6,7 1Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand; 2Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand; 4Nanotec-CU Center of Excellence on Food and Agriculture, Bangkok, Thailand; 5Department of Ophthalmology, Biomedical Engineering, Chemical and Biomolecular Engineering, Neurosurgery, and Oncology, Johns Hopkins University School of Medicine, 6Department of Neurosurgery, University of Maryland School of Medicine, 7Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA Abstract: Garcinia mangostana Linn extract (GME) is a natural product that has received considerable attention in cancer therapy, and has the potential to reduce side effects of chemotherapeutics and improve efficacy. We formulated GME-encapsulated ethyl cellulose (GME-EC) and a polymer blend of ethyl cellulose and methyl cellulose (GME-EC/MC) nanoparticles. We achieved high drug-loading and encapsulation efficiency using a solvent-displacement method with particle sizes around 250 nm. Cellular uptake and accumulation of GME was higher for GME-encapsulated nanoparticles compared to free GME. In vitro cytotoxicity analysis showed effective anticancer activity of GME-EC and GME-EC/MC nanoparticles in HeLa cells in a dose-dependent manner. GME-EC/MC nanoparticles showed approximately twofold-higher anticancer activity compared to GME-EC nanoparticles, likely due to their enhanced bioavailability. GME-encapsulated nanoparticles primarily entered HeLa cells by clathrin-mediated endocytosis and trafficked through the endolysosomal pathway. As far as we know, this is the first report on the cellular uptake and intracellular trafficking mechanism of drug-loaded cellulose-based nanoparticles. In summary, encapsulation of GME using cellulose-derivative nanoparticles – GME-EC and GME-EC/MC nanoparticles – successfully improved the bioavailability of GME in aqueous solution, enhanced cellular uptake, and displayed effective anticancer activity. Keywords: phytotherapy, cancer, nanoparticles, cellulose, intracellular trafficking

Aim: To combat the resistance of Helicobacter pylori to antibiotics through the use of Garcinia mangostana extract (GME) in the form that can be localized at stomach mucosa. Materials & methods: GME and its major active component, α-mangostin, are encapsulated into the moderately acid stable mucoadhesive nanocarriers, and tested for anti-H. pylori and antiadhesion activities in vitro and their ability to eradicate H. pylori in infected mice. Results: The two in vitro activities are observed and are enhanced when the materials are encapsulated into nanocarriers. Preliminary in vivo tests revealed the ability to combat H. pylori in mice following oral administration of the encapsulated GME, but not the unencapsulated GME. Conclusion: Nanoencapsulated GME is a potential anti-H. pylori agent. Original submitted 10 August 2012; Revised submitted 9 December 2012; Published online 3 June 2013